local _tl_compat;
if (tonumber((_VERSION or ''):match('[%d.]*$')) or 0) < 5.3 then
    local p, m = pcall(require, 'compat53.module');
    if p then
        _tl_compat = m
    end
end ;
local math = _tl_compat and _tl_compat.math or math;
local string = _tl_compat and _tl_compat.string or string;
local table = _tl_compat and _tl_compat.table or table
local inspect = { Options = {}, }

inspect._VERSION = 'inspect.lua 3.1.0'
inspect._URL = 'http://github.com/kikito/inspect.lua'
inspect._DESCRIPTION = 'human-readable representations of tables'
inspect._LICENSE = [[
  MIT LICENSE

  Copyright (c) 2022 Enrique García Cota

  Permission is hereby granted, free of charge, to any person obtaining a
  copy of this software and associated documentation files (the
  "Software"), to deal in the Software without restriction, including
  without limitation the rights to use, copy, modify, merge, publish,
  distribute, sublicense, and/or sell copies of the Software, and to
  permit persons to whom the Software is furnished to do so, subject to
  the following conditions:

  The above copyright notice and this permission notice shall be included
  in all copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
  CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
  TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
]]
inspect.KEY = setmetatable({}, { __tostring = function()
    return 'inspect.KEY'
end })
inspect.METATABLE = setmetatable({}, { __tostring = function()
    return 'inspect.METATABLE'
end })

local tostring = tostring
local rep = string.rep
local match = string.match
local char = string.char
local gsub = string.gsub
local fmt = string.format

local function rawpairs(t)
    return next, t, nil
end

local function smartQuote(str)
    if match(str, '"') and not match(str, "'") then
        return "'" .. str .. "'"
    end
    return '"' .. gsub(str, '"', '\\"') .. '"'
end

local shortControlCharEscapes = {
    ["\a"] = "\\a", ["\b"] = "\\b", ["\f"] = "\\f", ["\n"] = "\\n",
    ["\r"] = "\\r", ["\t"] = "\\t", ["\v"] = "\\v", ["\127"] = "\\127",
}
local longControlCharEscapes = { ["\127"] = "\127" }
for i = 0, 31 do
    local ch = char(i)
    if not shortControlCharEscapes[ch] then
        shortControlCharEscapes[ch] = "\\" .. i
        longControlCharEscapes[ch] = fmt("\\%03d", i)
    end
end

local function escape(str)
    return (gsub(gsub(gsub(str, "\\", "\\\\"),
            "(%c)%f[0-9]", longControlCharEscapes),
            "%c", shortControlCharEscapes))
end

local function isIdentifier(str)
    return type(str) == "string" and not not str:match("^[_%a][_%a%d]*$")
end

local flr = math.floor
local function isSequenceKey(k, sequenceLength)
    return type(k) == "number" and
            flr(k) == k and
            1 <= (k) and
            k <= sequenceLength
end

local defaultTypeOrders = {
    ['number'] = 1, ['boolean'] = 2, ['string'] = 3, ['table'] = 4,
    ['function'] = 5, ['userdata'] = 6, ['thread'] = 7,
}

local function sortKeys(a, b)
    local ta, tb = type(a), type(b)

    if ta == tb and (ta == 'string' or ta == 'number') then
        return (a) < (b)
    end

    local dta = defaultTypeOrders[ta] or 100
    local dtb = defaultTypeOrders[tb] or 100

    return dta == dtb and ta < tb or dta < dtb
end

local function getKeys(t)

    local seqLen = 1
    while rawget(t, seqLen) ~= nil do
        seqLen = seqLen + 1
    end
    seqLen = seqLen - 1

    local keys, keysLen = {}, 0
    for k in rawpairs(t) do
        if not isSequenceKey(k, seqLen) then
            keysLen = keysLen + 1
            keys[keysLen] = k
        end
    end
    table.sort(keys, sortKeys)
    return keys, keysLen, seqLen
end

local function countCycles(x, cycles)
    if type(x) == "table" then
        if cycles[x] then
            cycles[x] = cycles[x] + 1
        else
            cycles[x] = 1
            for k, v in rawpairs(x) do
                countCycles(k, cycles)
                countCycles(v, cycles)
            end
            countCycles(getmetatable(x), cycles)
        end
    end
end

local function makePath(path, a, b)
    local newPath = {}
    local len = #path
    for i = 1, len do
        newPath[i] = path[i]
    end

    newPath[len + 1] = a
    newPath[len + 2] = b

    return newPath
end

local function processRecursive(process,
                                item,
                                path,
                                visited)
    if item == nil then
        return nil
    end
    if visited[item] then
        return visited[item]
    end

    local processed = process(item, path)
    if type(processed) == "table" then
        local processedCopy = {}
        visited[item] = processedCopy
        local processedKey

        for k, v in rawpairs(processed) do
            processedKey = processRecursive(process, k, makePath(path, k, inspect.KEY), visited)
            if processedKey ~= nil then
                processedCopy[processedKey] = processRecursive(process, v, makePath(path, processedKey), visited)
            end
        end

        local mt = processRecursive(process, getmetatable(processed), makePath(path, inspect.METATABLE), visited)
        if type(mt) ~= 'table' then
            mt = nil
        end
        setmetatable(processedCopy, mt)
        processed = processedCopy
    end
    return processed
end

local function puts(buf, str)
    buf.n = buf.n + 1
    buf[buf.n] = str
end

local Inspector = {}

local Inspector_mt = { __index = Inspector }

local function tabify(inspector)
    puts(inspector.buf, inspector.newline .. rep(inspector.indent, inspector.level))
end

function Inspector:getId(v)
    local id = self.ids[v]
    local ids = self.ids
    if not id then
        local tv = type(v)
        id = (ids[tv] or 0) + 1
        ids[v], ids[tv] = id, id
    end
    return tostring(id)
end

function Inspector:putValue(v)
    local buf = self.buf
    local tv = type(v)
    if tv == 'string' then
        puts(buf, smartQuote(escape(v)))
    elseif tv == 'number' or tv == 'boolean' or tv == 'nil' or
            tv == 'cdata' or tv == 'ctype' then
        puts(buf, tostring(v))
    elseif tv == 'table' and not self.ids[v] then
        local t = v

        if t == inspect.KEY or t == inspect.METATABLE then
            puts(buf, tostring(t))
        elseif self.level >= self.depth then
            puts(buf, '{...}')
        else
            if self.cycles[t] > 1 then
                puts(buf, fmt('<%d>', self:getId(t)))
            end

            local keys, keysLen, seqLen = getKeys(t)

            puts(buf, '{')
            self.level = self.level + 1

            for i = 1, seqLen + keysLen do
                if i > 1 then
                    puts(buf, ',')
                end
                if i <= seqLen then
                    puts(buf, ' ')
                    self:putValue(t[i])
                else
                    local k = keys[i - seqLen]
                    tabify(self)
                    if isIdentifier(k) then
                        puts(buf, k)
                    else
                        puts(buf, "[")
                        self:putValue(k)
                        puts(buf, "]")
                    end
                    puts(buf, ' = ')
                    self:putValue(t[k])
                end
            end

            local mt = getmetatable(t)
            if type(mt) == 'table' then
                if seqLen + keysLen > 0 then
                    puts(buf, ',')
                end
                tabify(self)
                puts(buf, '<metatable> = ')
                self:putValue(mt)
            end

            self.level = self.level - 1

            if keysLen > 0 or type(mt) == 'table' then
                tabify(self)
            elseif seqLen > 0 then
                puts(buf, ' ')
            end

            puts(buf, '}')
        end

    else
        puts(buf, fmt('<%s %d>', tv, self:getId(v)))
    end
end

function inspect.inspect(root, options)
    options = options or {}

    local depth = options.depth or (math.huge)
    local newline = options.newline or '\n'
    local indent = options.indent or '  '
    local process = options.process

    if process then
        root = processRecursive(process, root, {}, {})
    end

    local cycles = {}
    countCycles(root, cycles)

    local inspector = setmetatable({
        buf = { n = 0 },
        ids = {},
        cycles = cycles,
        depth = depth,
        level = 0,
        newline = newline,
        indent = indent,
    }, Inspector_mt)

    inspector:putValue(root)

    return table.concat(inspector.buf)
end

setmetatable(inspect, {
    __call = function(_, root, options)
        return inspect.inspect(root, options)
    end,
})

return inspect
